A transparent product having a specific image visible from one side and substantially invisible from the opposite side of its surface is useful for presenting an advertisement by applying it to a glass surface. For this purpose, hologram, half mirror, and optical products having special visual effects such as pearl-like gloss have been used. For example, Japanese Unexamined Patent Publication (KOKAI) No. 2005-10195, the disclosure of which is expressly incorporated by reference herein in its entirety, discloses an electric advertising device with semi-transmissive and half-reflective half mirror in which an advertising display and a mirror display are exchanged by exchanging the backside light source. Japanese Unexamined Patent Publication (KOKAI) No. (Heisei) 11-65497, the disclosure of which is expressly incorporated by reference herein in its entirety, discloses an advertising device for automobile using a perforated plastic film, which has directionality such that from the bright outside only the advertisement can be seen and dark inside cannot be seen, and from the dark inside the bright outside view can be seen through the through-hole. Either device controls transmission and reflection ratio of the optical product and achieves the special visual effect by changing the balance of the brightness of both sides of the optical product.
However, the directionality is controlled only by the brightness of the environment in either case. Therefore, when the brightness of the environment changes because of night and day, for example, the directionality is damaged. Particularly, in the transmissive type device that is to be seen from the both sides as the device disclosed in Japanese Unexamined Patent Publication (KOKAI) No. (Heisei) 11-65497, the advertising display becomes disturbance as the bright outside is seen through from the dark inside. When the advertisement of Japanese Unexamined Patent Publication (KOKAI) No. (Heisei) 11-65497 is used for advertisement on the window of a building, visibility from the inside of the building has been improved compared to an advertisement with a normal printing but total invisibility has not been achieved.